High Performance Computing – Introduction to Unix

High Performance Computing – Introduction to Unix Robert Whitten Jr

Welcome! • Today’s Agenda: • Questions from last week • The basics • What is Unix? • Unix commands you can’t live without

From last week… • Send me an email • whittenrm1@ornl.gov • In subject line include [hpcc] so I can sort it • Tell me about yourself in the email • Name • Email • What you’d like to get out of the class • Something interesting about yourself • I’ve received about a half dozen so far

Homework assignment! • Get an account on smoky • http://www.nccs.gov/user-support/access/account-request/ • Box 1 = click yes to both questions • Box 2 = Name, etc • Box 3 = Citizenship • Box 4 = Current mailing address • Box 5 = Click ‘University’, scroll down put university in box at bottom • Box 6 = Type ‘Smoky’ in text box, • Box 7 = PI = “Robert Whitten Jr’, ProjectID=“CSC050”, Description = “HPC Scientific Computing Course”, click “No” for remaining questions • Box 8 = Nothing required • Click submit

The basics • Hardware • Software • Application software • System software

Hardware • Everything that can be touched in a computer • Microprocessor • Primary memory • Secondary memory • Network cables • Printers • Keyboards, mice, etc

Software • Programming used to be difficult • Rewire the whole machine each time • Makes the hardware usable • System software (operating systems) • Controls hardware • Applications do not need to know how to use hardware • Kernel vs. utilities • GUI vs. CLI • Application software • Word processing • Spreadsheets • Games

Unix • Operating system • Developed in early ‘70s by AT&T at Bell Labs • Multi user system • Unix has come to mean any Unix-like operating system • Andrew Tanenbaum created Minix • Textbook demonstration • Linus Torvalds created Unix-like kernel • Linux was born • Technically linux is the kernel only

Unix characteristics • Multi-user operation • Accounts for users • Permissions based • Command line interface (CLI) • No GUI (sort of) • X11 is a standard for doing GUI on unix systems • Utility programs • Navigate system • Execute programs • Device management through files

Unix characteristics • Data security • Permissions based • Read / write / execute • File system based • Data processing through filters • Text manipulating programs used heavily

Unix – accounts • All users have a distinct account name • i.e. bob, mary, userx11, superdude, etc • All accounts have passwords • Don’t use common passwords (name, birthday, ‘password’, etc) • Authentication vs. authorization • All accounts have a default home directory • More on file systems and directories in a bit • All accounts have configuration files • For individual preferences • All accounts have a command interpreter • Program that accepts and executes commands

Unix - permissions • All data is stored in files • Files are collections of data lumped together • Addresses, recipes, raw data, etc • All files have permissions • Read / write / execute • Permissions based on: • Who you are & what group you are in • Permissions are divided into three categories

Unix - permissions • Example: -rw-r--r-- 1 rmwjr ccsstaff 303 Aug 28 14:21 staff 222 Jun 4 mpi.pbs • Close up: -rw-r--r--

Unix – commands you can’t live without • passwd – change local password • man – read system manual pages • pwd – identify the working directory • cd – change the working directory • echo – display a string • ls – display contents of directory • cat – display text of file • more – display text of file • cp – copy a file • mv – move a file • rm – remove a file • mkdir – create a directory • rmdir – remove a directory

Unix file system • Hierarchical file structure • Directories • Files • Directories • Contain files and/or other directories (subdirectories) • Files • Contain data (text, binary, etc)

Hierarchical (tree) file system • There is one parent directory per file system • Root aka ‘/’ • Everything else is contained in this directory • Subdirectories • Files • Pathnames – name (address) of the file/directory • /ccs/home/rmwjr • Absolute vs. relative pathnames • Navigating directories • Creating files, directories • Redirection, pipes

Shell scripts • Programs to help automate recurring task • Text files that are interpreted by shell program • Interpreted vs compiled languages • Example

Homework! • Send me that email if you haven’t already whittenrm1@ornl.gov • Apply for an account http://www.nccs.gov/user-support/access/account-request/ • Download and install cygwin • Here’s how…. • Next week we’ll be playing with Unix commands • Download putty.exe • Here’s how….

Questions? http://www.nccs.gov Oak Ridge National Laboratory U. S. Department Of Energy19

High Performance Computing – Introduction to Unix